WO2023034628A2 - Mélange comprenant une phase nématique ferroélectrique et procédés de formation et d'utilisation de celui-ci - Google Patents

Mélange comprenant une phase nématique ferroélectrique et procédés de formation et d'utilisation de celui-ci Download PDF

Info

Publication number
WO2023034628A2
WO2023034628A2 PCT/US2022/042586 US2022042586W WO2023034628A2 WO 2023034628 A2 WO2023034628 A2 WO 2023034628A2 US 2022042586 W US2022042586 W US 2022042586W WO 2023034628 A2 WO2023034628 A2 WO 2023034628A2
Authority
WO
WIPO (PCT)
Prior art keywords
molecules
molecule
functional group
end functional
phase
Prior art date
Application number
PCT/US2022/042586
Other languages
English (en)
Other versions
WO2023034628A3 (fr
Inventor
Joseph E. MACLENNAN
Noel A. CLARK
Matthew A. GLASER
Xi Chen
Gregory Smith
Original Assignee
The Regents Of The University Of Colorado, A Body Corporate
Priority date (The priority date is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the date listed.)
Filing date
Publication date
Application filed by The Regents Of The University Of Colorado, A Body Corporate filed Critical The Regents Of The University Of Colorado, A Body Corporate
Publication of WO2023034628A2 publication Critical patent/WO2023034628A2/fr
Publication of WO2023034628A3 publication Critical patent/WO2023034628A3/fr

Links

Classifications

    • C—CHEMISTRY; METALLURGY
    • C09—DYES; PAINTS; POLISHES; NATURAL RESINS; ADHESIVES; COMPOSITIONS NOT OTHERWISE PROVIDED FOR; APPLICATIONS OF MATERIALS NOT OTHERWISE PROVIDED FOR
    • C09K—MATERIALS FOR MISCELLANEOUS APPLICATIONS, NOT PROVIDED FOR ELSEWHERE
    • C09K19/00—Liquid crystal materials
    • C09K19/02—Liquid crystal materials characterised by optical, electrical or physical properties of the components, in general
    • C09K19/0225—Ferroelectric
    • C—CHEMISTRY; METALLURGY
    • C09—DYES; PAINTS; POLISHES; NATURAL RESINS; ADHESIVES; COMPOSITIONS NOT OTHERWISE PROVIDED FOR; APPLICATIONS OF MATERIALS NOT OTHERWISE PROVIDED FOR
    • C09K—MATERIALS FOR MISCELLANEOUS APPLICATIONS, NOT PROVIDED FOR ELSEWHERE
    • C09K19/00—Liquid crystal materials
    • C09K19/04—Liquid crystal materials characterised by the chemical structure of the liquid crystal components, e.g. by a specific unit
    • C09K19/06—Non-steroidal liquid crystal compounds
    • C09K19/08—Non-steroidal liquid crystal compounds containing at least two non-condensed rings
    • C09K19/10—Non-steroidal liquid crystal compounds containing at least two non-condensed rings containing at least two benzene rings
    • C09K19/20—Non-steroidal liquid crystal compounds containing at least two non-condensed rings containing at least two benzene rings linked by a chain containing carbon and oxygen atoms as chain links, e.g. esters or ethers
    • C09K19/2007—Non-steroidal liquid crystal compounds containing at least two non-condensed rings containing at least two benzene rings linked by a chain containing carbon and oxygen atoms as chain links, e.g. esters or ethers the chain containing -COO- or -OCO- groups
    • C09K2019/2078—Ph-COO-Ph-COO-Ph
    • C—CHEMISTRY; METALLURGY
    • C09—DYES; PAINTS; POLISHES; NATURAL RESINS; ADHESIVES; COMPOSITIONS NOT OTHERWISE PROVIDED FOR; APPLICATIONS OF MATERIALS NOT OTHERWISE PROVIDED FOR
    • C09K—MATERIALS FOR MISCELLANEOUS APPLICATIONS, NOT PROVIDED FOR ELSEWHERE
    • C09K19/00—Liquid crystal materials
    • C09K19/04—Liquid crystal materials characterised by the chemical structure of the liquid crystal components, e.g. by a specific unit
    • C09K19/06—Non-steroidal liquid crystal compounds
    • C09K19/34—Non-steroidal liquid crystal compounds containing at least one heterocyclic ring
    • C09K19/3402—Non-steroidal liquid crystal compounds containing at least one heterocyclic ring having oxygen as hetero atom
    • C09K2019/3422—Non-steroidal liquid crystal compounds containing at least one heterocyclic ring having oxygen as hetero atom the heterocyclic ring being a six-membered ring

Definitions

  • the present disclosure generally relates to material comprising a ferroelectric nematic phase. More particularly, the disclosure relates to material comprising a mixture comprising a ferroelectric nematic phase, to methods of forming the material, and to devices including the material.
  • Ferroelectricity in liquids was predicted in the 1910s by P. Debye and M. Bom, who applied the Langevin-Weiss model of ferromagnetism to the orientational ordering of molecular electric dipoles. Recently, interest in nematic ferroelectricity has gained interest. Nematic ferroelectricity presents opportunities for novel liquid crystal science and technology thanks to its unique combination of macroscopic polar ordering and fluidity.
  • the ferroelectric nematic (NF) phase of RM734 shows a rapid electro-optic response at high temperature in the NF range but exhibits crystallization and a viscosity that grows strongly on slow cooling.
  • the room temperature NF phase that is obtained by quenching, on the other hand, is glassy. Accordingly, improved materials that exhibit nematic ferroelectricity are generally desirable.
  • Embodiments of the disclosure relate to a material comprising a ferroelectric nematic phase.
  • the material can include a mixture comprising first molecules and second molecules, wherein at least one of a fluid of the first molecules and a fluid of the second molecules exhibits a ferroelectric nematic phase, wherein the first molecules and second molecules are miscible, and wherein the first molecules induce a polar orientational order of said second molecules.
  • the first molecules and the second molecules are chemically dissimilar.
  • chemically dissimilar can be defined by molecular similarity coefficients S computed from molecular topology-based fingerprints (vector representations of chemical structures).
  • Pairs of distinct molecules with S ⁇ 0.33 are highly dissimilar and pairs with S > 0.8 are highly similar.
  • chemically dissimilar can be S ⁇ 0.75, 0.5, 0.33, or 0.3.
  • At least one of the first molecules and the second molecules comprise a halogen. In accordance with further examples, at least one of the first molecules and the second molecules do not comprise a halogen. In some cases, at least one of the first molecules and the second molecules can include a plurality of halogen atoms.
  • the first molecules each comprise a first backbone, a first molecule first end functional group and a first molecule second end functional group
  • the second molecules each comprise a second backbone, a second molecule first end functional group and a second molecule second end functional group. In some cases, the (e.g., chemical structure of the) first backbone and the second backbone differ.
  • the first molecule first end functional group differs from the second molecule first end functional group and/or the first molecule second end functional group differs from the second molecule second end functional group.
  • One or more of the end groups can include a halogen (such as fluorine), an alkyl group, or an alkoxy group.
  • the backbone can include 3 or 4 ring structures, at least one linker group, and optionally a side group on one or more of the ring structures.
  • Exemplary ring structures include, for example, phenyl ring, a cyclohexane ring, a dioxane ring, a thiophene ring, a monoxane ring, a pyridine ring, a pyrimidine ring, or any other heterocyclic group, and the like.
  • the material can include one or more additional molecules miscible within the mixture.
  • a non-linear optic material can include material as described herein.
  • a method of forming a material having a timable ferroelectric nematic phase includes mixing of first molecules and second molecules to form a mixture having a ferroelectric nematic phase, wherein the first molecules induce a polar orientational order of said second molecules.
  • the first, second, and any additional molecules can be as described above.
  • the first molecules comprise RM734 and the second molecules comprise DIO.
  • a device including electronic electro-optic and nonlinear devices, can include one or more (e.g., two) electrodes and a material/mixture as described herein.
  • FIG. 1 illustrates RM734 and DIO, which are representative members of nitro- and fluoro- based molecular families that exhibit novel polar nematic phases.
  • Ferroelectric nematics (NF) have been observed independently in both materials, and in close homologs within each family.
  • DIO exhibits, in addition, an intermediate phase, the SmZA, recently shown to be an antiferroelectric smectic.
  • FIG. 2 illustrates a synthesis scheme for DIO in accordance with examples of the disclosure.
  • FIG. 3 illustrates a phase diagram of the RM734 and DIO binary mixture.
  • the phase transition temperatures were determined using polarized light microscopy, DSC, and polarization current measurements. Continuous miscibility within the Iso, N, and N F phases indicates that they are the same in RM734 and DIO.
  • the transitions are first-order, with average entropy changes across the phase diagram of: 0.01)R.
  • the N/SmZA transition is ultra-weakly first-order ( ⁇ - ⁇ S-0.001R for DIO).
  • the SmZA phase of DIO which is not observed for c ⁇ 50 wt%, has been identified as an antiferroelectric smectic. This phase is lamellar and density-modulated, with the director parallel to the plane of the layers, and the polarization alternating in sign from layer to layer.
  • the effective orientational viscosity of the mixtures, ⁇ increases rapidly on cooling, reaching ⁇ 5 Pa • s at the dashed line, heralding the approach to an orientational glass transition. Crystallization is not observed in the glass but occurs at either end of the phase diagram soon ( ⁇ 1 hr) after cooling the mixtures into the gray areas.
  • FIG. 4 illustrates domain evolution and field response in the NF phase of neat DIO.
  • the boundary between domains with opposite twist is a 2 ⁇ -twist disclination line.
  • the initial optically uniform (U) state sketched at right which has a localized polarization reversal wall in the interior of the cell, transitions to a continuous ⁇ -twist state by passage of a ⁇ -twist surface line. While the uniform state can be extinguished between crossed polarizer and analyzer, the twist state remains birefringent independent of sample orientation.
  • the scale is the same in all images.
  • A In the N phase, the director field is uniform (U) and along the buffing direction.
  • B This condition is initially retained in the NF, once the phase front (dashed white line), characterized by the temporary appearance of irregular, polar domains extended along the director, passes through the cell.
  • C With a few degrees of additional cooling in the NF phase, ⁇ -twist states stabilized by the increasingly strong antipolar surface anchoring nucleate and grow in the previously uniform NF region.
  • FIG. 6 illustrates characteristics of polarization reversal in DIO/RM734 mixtures.
  • a 50 Hz square wave with a peak amplitude of 104 V, applied to ITO electrodes with a 1 mm gap in a d 8 ⁇ m thick, planar aligned, cell, results in an in-plane field of 69 V/mm in the center of the gap.
  • This relatively small field is large enough to achieve full reversal of the bulk polarization in the N F phase at higher temperatures.
  • the polarization is determined by integrating the current through the cell over one half-cycle of the driving voltage (10 msec).
  • P sat (c) The maximum polarization, P sat (c), indicated with white squares here and in (D), is measured at a temperature T sat , below which the director reorientation slows down and the polarization reversal is incomplete (solid circles), so that Q reflects only part of the true polarization density (Q ⁇ 2AP), which, based on computer simulations and additional measurements, increases weakly from P sat (c) as T is decreased from T sat .
  • FIG. 7 illustrates temperature dependence of (A) polarization and (B) scaled viscosity in DIO/RM734/W1027 ternary mixtures.
  • FIG. 8 illustrates (A) Schematic of NLO chromophore molecules incorporated into N F mixtures such as PM158, consisting of an electron donor, pi-conjugated bridge, and electron acceptor. Such 'push-pull' molecules have large electric dipole moments and large first hyperpolarizabilities.
  • B Measured temperature dependence of ferroelectric polarization density P for PM146 (black squares), an N F mixture containing no NLO chromophore molecules, and for PM158 (red circles), an N F mixture obtained by adding 25% by weight of NLO chromophores to PM146.
  • C Distorted state induced by twist Freedericksz transition when an in-plane E field is applied to the previously uniform state.
  • FIG. 10 illustrates temperature dependence of Freedericksz transition thresholds in the N phase of RM734 and DIO.
  • In-plane applied fields generate twist deformation of the director while fields normal to the cell plates generate splay-bend deformation.
  • a 200 Hz square-wave field was applied in both cases.
  • the observed splay- bend threshold voltages agree well with calculated using the Ks and ⁇ values given elsewhere.
  • Both RM734 and DIO exhibit a general increase in ⁇ with decreasing T.
  • the Freedericksz thresholds are lower in RM734 and decrease rapidly on approaching the transition to the N F phase due to the strong pretransitional growth of ⁇ , a phenomenon which does not occur in DIO, where the transition on cooling is to the SmZA phase.
  • FIG. 11 illustrates polarization current response to applied field reversal vs. temperature in mixtures with differing DIO concentration.
  • the inset plots show the response at the lowest temperatures.
  • the corresponding charge density, Q/2A is plotted in FIG. 6 (B), where A is the cross-sectional area of the liquid crystal sample in the plane normal to the applied field midway between the two electrodes.
  • FIG. 12 illustrates phase diagram of RM734/DIO binary mixtures illustrating their enantiotropic behavior.
  • the transition temperatures were determined on heating using polarized light microscopy and polarization current measurements in cells prepared several months earlier.
  • the N F phase was observed to be enantiotropic in all of the mixtures.
  • the SmZA phase was found to be enantiotropic in mixtures with concentrations in the range of 40 to 90% DIO.
  • FIG. 13 illustrates comparison of wide-angle X-ray scattering from RM734 and DIO.
  • FIG. 14 illustrates Line scans, I(qz), of WAXS images of scattering from DIO and RM734.
  • any two numbers of a variable can constitute a workable range of the variable, and any ranges indicated may include or exclude the endpoints.
  • any values of variables indicated may refer to precise values or approximate values and include equivalents, and may refer to average, median, representative, majority, the value ⁇ 10 % (e.g., vol. at. or mass %0, or the like.
  • the terms "including,” “constituted by” and “having” can refer independently to “typically or broadly comprising,” “comprising,” “consisting essentially of,” or “consisting of” in some embodiments. In this disclosure, any defined meanings do not necessarily exclude ordinary and customary meanings.
  • Nematic ferroelectricity presents opportunities for novel liquid crystal science and technology thanks to its unique combination of macroscopic polar ordering and fluidity.
  • the ferroelectric nematic (N F ) phase of, for example, RM734 shows a rapid electro-optic response at high temperature in the N F range but exhibits crystallization and a viscosity that grows strongly on slow cooling.
  • the exploration of mixtures is an approach to addressing issues such as eliminating crystallization, expanding phase ranges, and tuning liquid crystal properties.
  • Studies of mixtures are also key to advancing liquid crystal science, providing a way to test structural models of phases by continuously varying the composition, to find phases in mixtures that are not exhibited by any of their components, and to discover new phases.
  • Phase Diagram - RM734 and DIO were synthesized using schemes shown in FIG. 1.
  • PLM polarized light microscopy
  • DSC differential scanning calorimetry
  • SAXS experiments is shown in FIG. 3.
  • a well-defined phase front passing through the cell was observed in the microscope at each of the transitions, allowing an accurate determination of the transition temperatures.
  • the observed transition temperatures of the neat components agree well with the published values.
  • N paraelectric nematic
  • SmZA antiferroelectric smectic Z
  • N F ferroelectric nematic
  • Iso Isotropic Phase
  • the Iso phase shows extinction of transmitted light between crossed polarizer and analyzer and exhibits no detectable response to applied fields of up to 100 V/mm.
  • N paraelectric Nematic Phase
  • n(r) a uniform, in-plane director field
  • Excellent extinction is achieved when the cell is oriented with the director parallel to the polarizer or analyzer (FIGS. 5 (A), 9 (B)).
  • the transition to the N F is marked by an increase in the threshold for the splay-bend Freedericksz transition, from a few tenths of a volt in the N phase to more than one hundred volts in the N F phase, a result of the large electrostatic energy cost of rotating the ferroelectric polarization P in an initially planar cell to give a component normal to the cell plates.
  • the threshold field for in-plane field-induced twist is reduced by about a factor of 1000 because of the development of ferroelectric coupling between P and E, giving extreme electro-optic responsivity in very weak applied in-plane electric fields (in the 0.1 to 1 V/mm range) in all of the N F director states shown.
  • nematic ferroelectricity a spontaneous uniform to ⁇ -twisted transition in an antiparallel- buffed cell in the N F phase is a uniquely ferroelectric nematic phenomenon, requiring not only macroscopic polar ordering of the bulk LC but also polar coupling to a macroscopically polar surface.
  • the LH and RH ⁇ -twist states support, respectively, a half-turn of a left- or right-handed director helix and are separated by topological 2 ⁇ -twist lines.
  • the two twist states have opposite net polarization, normal to the buffing axis, so that reversing an electric field applied in this direction can be used to switch between them, as shown in FIG.
  • the length scale of the coarsening domains has been observed to increase continuously on cooling to millimeter dimensions, with irregular, macroscopic patterns of reversed polarization extended along the director, as seen in RM734 and in a homolog of DIO that transitions directly from N to N F .
  • the uniform N F domains are separated either by pure polarization reversal walls or by splay-bend walls. This behavior, along with the ferroelectric uniform and twisted states observed in DIO, suggest that the N F phase observed in the mixtures is the same as that in RM734 and DIO.
  • the transition sequence on cooling is first N - SmZA and then SmZA - N F .
  • These transitions are weakly first-order, and the phases grow in as optically distinct, uniform domains upon cooling, without the dramatic polar fluctuations seen at the N - N F transition.
  • Over most of the SmZA phase in-plane reorientation of the director field is strongly suppressed but at lower temperatures, approaching the transition to the N F phase, ferroelectric fluctuations appear and the susceptibility for field-induced reorientation increases, to be discussed in a later publication.
  • This signal corresponds to the RC-drcuit linear response of the cell and series resistance, giving the initial upward curvature of the measured P, due to increasing E in the N phase as the N F is approached in T.
  • a much larger current signal resulting from the reversal of spontaneous polarization in the sample, appears at longer times.
  • the saturation value of the polarization is similar in all of the mixtures, P sat ⁇ 6 pC/cm 2 , as seen in FIG. 6 (B), with P sat (c) decreasing slightly from the RM734-rich to the DIO-rich end, as shown in FIG. 6 (D).
  • crystallization is observed on cooling in mixtures at both ends of the phase diagram, near c ⁇ 0 and c ⁇ 100%, as crystallization becomes thermodynamically favorable at higher temperatures where the fluid N F phase still has relatively low viscosity (gray Xtal regions in FIG. 3).
  • the precipitous reduction in the measured charge density at the lowest temperatures coincides with a sudden increase in switching time, which results from a rapid rise in the effective orientational viscosity on approaching the glassy state.
  • Polarization Reorientation Dynamics Orientational Viscosity Measurement -
  • q the orientational viscosity, which is strongly dependent on T in the N F phase.
  • Polarization reversal takes this long because under conditions of rapid field reversal, P is generally oriented antiparallel to E immediately after the field switches, at a very low-torque orientation through most of the cell volume.
  • the measured viscosity of all of the mixtures is r) ⁇ 0.05 Pa • s at the highest temperatures in the NF phase, increasing on cooling to r) ⁇ 3 Pa • s at the longest measurable times (when TR reaches 10 msec).
  • the viscosity of each mixture shows a nearly Arrhenius-type dependence on temperature (FIG. 6(C)), suggestive of a barrier-limited dissipation process.
  • the experimental data do generally exhibit upward curvature, trending above the Arrhenius line at the lowest temperatures, which we attribute to the approach to a transition to a glassy state.
  • FIG. 7 (A) The polarization vs. temperature of the three-component DIO/RM734/W1027 mixture described in the text is plotted in FIG. 7 (A).
  • the scaled viscosity of this mixture is plotted in FIG. 7 (B).
  • TNF(C) the center temperature of the phase coexistence range at the transition to the NF phase
  • SvL Schroeder - van Laar
  • the N - NF transition is direct and first order, whereas at the DIO end, the phase sequence involves two first-order transitions: N - SmZA - NF.
  • the linear variation of T(x) vs. x is maintained irrespective of whether the transition into the NF is from the N or the SmZA phase. Since T(x) is governed by the intersection of the Gibbs free energy surfaces governing the N - NF transition, which linearly interpolate between those of the pure components, the linearity of T(x) suggests that the thermodynamic effect of the N - SmZA transition is minor.
  • the current proposed models for the phase change from the quadrupolar but nonpolar N phase to the quadrupolar and polar NF phase are that it is either a first-order Landau-de Gennes mean-field transition, or an Ising-like orientational transition of molecular dipoles having a binary choice of orientations (along +n or -n), made first-order by long-range dipoledipole interactions.
  • the polarization P(T) is the principal order parameter of the transition.
  • FIG. 6 (B) shows that the growth of P(T) is similar for the different concentrations
  • the transition to the NF has been found to be first-order and mean-field-like, and exhibit highly anisotropic orientational correlations in the N phase, features which can be understood with a model that includes the effects of the long-range dipole-dipole interactions on the fluctuations in the N phase.
  • the critical behavior of Ising systems with long-range interactions has been studied extensively in the context of certain magnetic materials that have short-range ferromagnetic exchange forces, but where the long-range dipolar interactions are also important.
  • the dipole-dipole (third) term produces extended correlations that grow as along x and y but as along z, suppressing x(q) for finite q z as is observed qualitatively from the image sequences of the textures upon passing through the phase transition, and from their optical Fourier transforms. Because of this anisotropy, the correlation volume in this model grows in 3D as rather that the isotropic reducing the upper marginal dimensionality of the transition to three and making the transition mean-field-like with logarithmic corrections, rather than fluctuation-dominated with 3D Ising universality.
  • the coefficient A in contrast, varies substantially with c, behavior which can be quantified by measuring the viscosity vs. concentration at a single temperature, for example 80 o C. The plot in FIG.
  • Enantiotropic NF and SmZA phases All single-component N F materials reported to date, including RM734 and DIO, are monotropic, with the N F phase observed only on cooling, implying that the N F state is thermodynamically metastable relative to the crystalline state. When held at a fixed temperature in the N F state, such single-component materials eventually crystallize, on timescales ranging from seconds to days. For practical applications of N F materials, enantiotropic behavior (i.e., a thermodynamically stable N F phase) is highly desirable.
  • the SmZA phase which is observed in the heating experiments over a wide range of compositions, is also enantiotropic, in contrast to neat DIO, in which the SmZA is monotropic.
  • Table 1 Upper and lower temperature bounds of the enantiotropic N F phase depicted in FIG 12.
  • nematics were found to be dielectric and nonpolar in the absence of a field, separated from the isotropic by a first-order phase transition with transition enthalpies ⁇ 1 kj/mol, and optically uniaxial, with a birefringence that increased slowly with decreasing temperature or increasing concentration. It has been shown that anisotropic steric shape and/or van der Waals forces, employed to describe intermolecular interactions in simple mean-field or second virial statistical mechanical models, were the molecular features required to get a basic description of nematic ordering.
  • FIG. 3 and Table 1 summarize the observed phase behavior of the Li compounds as pure materials, dividing them into three categories: (9 molecules) - exhibiting an enantiotropic N F phase; (12 molecules) - exhibiting a monotropic N F phase that was difficult to study because of rapid crystallization; and (21 molecules) - exhibiting no N F phase.
  • DIO and RM734 have similar dipole moments ( ⁇ 11 D) and charge distributions characterized by an alternation in the sign of charge along the length of the molecule, features that are strongly correlated with typical pair-association motifs (e.g., head-to-tail 'chaining' and side- by-side 'docking') observed in atomistic simulations of RM734 and related compounds.
  • the role of longitudinal charge density modulation in stabilizing the N F phase has also recently been addressed in theoretical work.
  • N F materials are highly unusual polar solvents that quite generally induce polar orientational order in dipolar solute molecules, a phenomenon we term 'solvent poling'.
  • the organic mesogens RM734 and DIO are members of separate molecular families featuring distinct molecular structures. These families are known to exhibit a ferroelectric nematic liquid crystal (LC) phase.
  • LC ferroelectric nematic liquid crystal
  • N and N F paraelectric nematic phases in both materials, each of which exhibits complete miscibility across the phase diagram, showing that the paraelectric and ferroelectric are the same phases in RM734 as in DIO.
  • these molecules form ideal mixtures with respect to both the paraelectric-ferroelectric nematic phase behavior and the ferroelectric polarization density of the mixtures, the principal order parameter of the transition.
  • Ideal mixing is also manifested in the orientational viscosity, and the onset of glassy dynamics at low temperature. This behavior is attributable in part to the similarity of their overall molecular shape and net longitudinal dipole moment ( ⁇ 11 Debye), and to a common tendency for head-to-tail molecular association.
  • ⁇ 11 Debye overall molecular shape and net longitudinal dipole moment
  • the significant difference in molecular structures leads to poor solubility in the crystal phases, enhancing the stability of the ferroelectric nematic phase at low temperature in the mixtures and making possible room temperature electro-optic effects.
  • an intermediate phase appears via an ultraweak, first-order transition from the N phase, in a narrow temperature range between the paraelectric and ferroelectric nematics.
  • reaction mixture was stirred at room temperature for 4 days, then filtered, washed with water, and with brine, dried over MgSCU, filtered, and concentrated at reduced pressure.
  • the resulting product was purified by flash chromatography (silica gel, petroleum ether/10% ethyl acetate). The crude product was crystallized by dissolving in boiling 75 mL petroleum ether/20% ethyl acetate solvent mixture, followed by cooling down to -20 °C for 1 hour, yielding 2.98 g (49%) white needles of compound 3.
  • W1027 was synthesized according to the scheme sketched in FIG. 2 and described below. Starting materials and reagents were used as purchased from qualified suppliers without additional purification. Intermediates 4 and 5 were purchased from Sigma -Aldrich Inc., USA. 2,4-dimethoxybenzoyl chloride (4) (1.41 g, 7.1 mmol) and 4-hydroxy-4'-nitrobiphenyl (1.52g, 7.1 mmol) were dissolved in tetrahydrofuran (50 ml), after which triethylamine (0.862 g, 8.5 mmol, 1.2 ml) was added dropwise.
  • Mixtures - RM734 and DIO were synthesized using respectively the schemes shown in FIG. 2 Samples of the two materials were weighed separately, melted into the isotropic phase, and mixed thoroughly by stirring at 200 o C. The mixtures were studied using standard liquid crystal phase analysis techniques including polarized light microscopy (PLM), differential scanning calorimetry (DSC), and small- and wide-angle x-ray scattering (SAXS and WAXS), as well as combined polarization measurement/electro-optic techniques, for establishing the appearance of spontaneous ferroelectric polarization, determining its magnitude, and measuring electro-optic response. DSC studies of RM734, DIO and their mixtures were performed on a Mettler Toledo STARe system calorimeter. The entropy change at the N - SmZ A transition was too small to be observed.
  • PLM polarized light microscopy
  • DSC differential scanning calorimetry
  • SAXS and WAXS small- and wide-angle x-ray scattering
  • Electro-optics For electro-optical characterization, the mixtures were generally filled into planar-aligned, in-plane switching test cells with uniform thickness d in the range 3.5 ⁇ m ⁇ d ⁇ 8 ⁇ m obtained from Instec, Inc.
  • In-plane indium-tin oxide (ITO) electrodes on one of the glass plates were spaced 1 mm apart. Alignment layers were unidirectionally buffed, antiparallel on the two plates, in a direction nearly parallel to the electrode edges. Such surfaces give quadrupolar alignment of the director along the buffing direction in the N and NA phases, and polar alignment at each plate in the N F phase.
  • ITO indium-tin oxide
  • the antiparallel buffing leads to ANTIPOLAR cells in the N F phase, with a director/polarization field in the plane of the cell but making a n twist between the plates.
  • FIG. 13 illustrates comparison of wide-angle X-ray scattering from RM734 and DIO.
  • the samples have the nematic director magnetically -aligned along z by a ⁇ 1 Tesla magnetic field.
  • the color/grey scale gamuts are linear in intensity, with the (black/darkest) minima corresponding to zero intensity.
  • Scattered intensity line scans, from such WAXS images are shown in FIG. 14
  • RM734 and DIO exhibit a strikingly similar characteristic WAXS scattering pattern that appears upon cooling into the N phase and does not change very much on cooling into the lower temperature phases, apart from the appearance of the SmZA layering peaks (visible in SAXS images).
  • the WAXS patterns exhibit familiar nematic diffuse scattering features at qz ⁇ 0.25 ⁇ -1 and q y ⁇ 1.4 ⁇ -1 , arising respectively from the end-to-end and side-by-side pair-correlations, that are typically generated by the steric rod-shape of the molecules and are located respectively at (2 ⁇ /molecular length - 0.25 ⁇ -1 ) and (27i/molecular width ⁇ 1.4 ⁇ -1 ).
  • RM734 In contrast to typical nematics, RM734 also exhibits an atypical series of scattering bands for q y ⁇ 0.4 ⁇ -1 and qz> 0.25 ⁇ -1 , initially reported in RM734 and its homologs. Interestingly, DIO presents a qualitatively very similar scattering pattern (A,B,D), but with an even more well-defined peak structure, likely a result of the higher variation of excess electron density along the molecule associated with the fluorines. Also notable is that the qz ⁇ 0.25 ⁇ -1 feature in RM734 is weak compared to that found in typical nematics such as 5CB and all- aromatic LCs.
  • I(( qz) the temperatures where the peak structures of I( qz) are the strongest, reveals common features. These include the previously reported intense diffuse scattering features at qz ⁇ 0.25 ⁇ -1 and q y ⁇ 1.4 ⁇ -1 , and the multiplicity of diffuse peaks along qz previously observed in the RM734 family. The pairs of similarly colored/shaded dots show analogous peaks for the two compounds.
  • the root mean square relative displacement of neighboring molecules along the chain, ⁇ ( ⁇ u 2 ) can be estimated from the ratio of the half- width at half maximum of the scattering peak at qzP (0.04 ⁇ -1 ) to qzP.

Landscapes

  • Chemical & Material Sciences (AREA)
  • Crystallography & Structural Chemistry (AREA)
  • Engineering & Computer Science (AREA)
  • Materials Engineering (AREA)
  • Organic Chemistry (AREA)
  • Pyrane Compounds (AREA)
  • Liquid Crystal Substances (AREA)
  • Liquid Crystal (AREA)

Abstract

L'invention concerne un matériau comprenant une phase nématique ferroélectrique, le matériau étant décrit. Le matériau peut comprendre un mélange comprenant des premières molécules et des secondes molécules. Au moins un fluide des premières molécules et un fluide des secondes molécules présente une phase nématique ferroélectrique. Les premières molécules et les secondes molécules sont miscibles. Les premières molécules peuvent induire un ordre d'orientation polaire desdites secondes molécules.
PCT/US2022/042586 2021-09-03 2022-09-05 Mélange comprenant une phase nématique ferroélectrique et procédés de formation et d'utilisation de celui-ci WO2023034628A2 (fr)

Applications Claiming Priority (4)

Application Number Priority Date Filing Date Title
US202163240666P 2021-09-03 2021-09-03
US63/240,666 2021-09-03
US202163278039P 2021-11-10 2021-11-10
US63/278,039 2021-11-10

Publications (2)

Publication Number Publication Date
WO2023034628A2 true WO2023034628A2 (fr) 2023-03-09
WO2023034628A3 WO2023034628A3 (fr) 2023-04-13

Family

ID=85412912

Family Applications (1)

Application Number Title Priority Date Filing Date
PCT/US2022/042586 WO2023034628A2 (fr) 2021-09-03 2022-09-05 Mélange comprenant une phase nématique ferroélectrique et procédés de formation et d'utilisation de celui-ci

Country Status (1)

Country Link
WO (1) WO2023034628A2 (fr)

Family Cites Families (2)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US7758773B2 (en) * 2002-01-10 2010-07-20 Kent State University Non-synthetic method for modifying properties of liquid crystals
DE102018003787A1 (de) * 2017-05-30 2018-12-06 Merck Patent Gmbh Flüssigkristallines Medium

Also Published As

Publication number Publication date
WO2023034628A3 (fr) 2023-04-13

Similar Documents

Publication Publication Date Title
Sebastián et al. Ferroelectric nematic liquid-crystalline phases
Pelzl et al. Banana‐shaped compounds—a new field of liquid crystals
Chen et al. Ideal mixing of paraelectric and ferroelectric nematic phases in liquid crystals of distinct molecular species
Kaur et al. The elastic and optical properties of a bent-core thiadiazole nematic liquid crystal: the role of the bend angle
CN105555917A (zh) 介晶化合物和介晶介质
Vita et al. Polar order in bent-core nematics: An overview
Eremin et al. Field-induced switching between states of opposite chirality in a liquid-crystalline phase
Kavitha et al. Study of optical shuttering action in supramolecular hydrogen bonded nematogens
Buka et al. Physical properties of a bent-core nematic liquid crystal and its mixtures with calamitic molecules
Škarabot et al. Flexoelectric polarization in a nematic liquid crystal enhanced by dopants with different molecular shape polarities
Gleeson et al. Dynamic properties of blue-phase mixtures
EP0632116B1 (fr) Composition liquide crystalline SmC et élément d'affichage
Schröder et al. Chiral domains of the SmCPA phase formed by cooling the isotropic liquid or by field-induced nucleation above the clearing temperature
Zhang et al. Electric-field-induced patterns in a hockey-stick nematic
WO2023034628A2 (fr) Mélange comprenant une phase nématique ferroélectrique et procédés de formation et d'utilisation de celui-ci
Kim et al. Optically isotropic liquid crystal media formulated by doping star-shaped cyclic oligosiloxane liquid crystal surfactants in twin nematic liquid crystals
Skarp et al. Anomalous current and electrooptic response in a polyacrylate ferroelectric liquid crystal with large spontaneous polarization
Urbańska et al. Effect of doping by enantiomers with the different absolute configuration and phase sequence on mesomorphic, helical and electro-optical properties of highly tilted chiral anticlinic mixture
Kaur et al. Polar response and Fréedericksz transition in cybotactic nematic fluids of unsymmetrical bent-core molecules
Demus Phase types, structures and chemistry of liquid crystals
Dunemann et al. A new class of bent‐shaped mesogens exhibiting unusual mesophase behaviour
Calucci et al. Orientational order, molecular organization, and dynamics in mixtures of bent-core and rod-shaped mesogens: a 2H NMR study
Zhong et al. Thermotropic reentrant isotropy and antiferroelectricity in the ferroelectric nematic realm: Comparing RM734 and DIO
Chakraborty Phase transitions in Binary mixtures of calamitic and Bent-Core-Mesogens
US7910180B2 (en) Liquid crystal and liquid crystal display

Legal Events

Date Code Title Description
121 Ep: the epo has been informed by wipo that ep was designated in this application

Ref document number: 22865646

Country of ref document: EP

Kind code of ref document: A2

WWE Wipo information: entry into national phase

Ref document number: 2022865646

Country of ref document: EP

ENP Entry into the national phase

Ref document number: 2022865646

Country of ref document: EP

Effective date: 20240315

NENP Non-entry into the national phase

Ref country code: DE

121 Ep: the epo has been informed by wipo that ep was designated in this application

Ref document number: 22865646

Country of ref document: EP

Kind code of ref document: A2